Python/ttk/tKinter - passing an argument with a button click func?

Question

I'm trying to pass an argument to a button click func and encountering an issues.

In short, I am trying to get a button press to pop up out the askColor() method, and return that colour value as the background colour of the related textbox.

Its function is so synaesthets can associate a colour with a letter/number and record the resulting colour list.

specific lines:

    self.boxA = Text(self.mainframe, state='normal', width=3, height=1, wrap='word', background=self.AVal).grid(column=2, row=2, padx=4)
    self.boxB = Text(self.mainframe, state='normal', width=3, height=1, wrap='word', background=self.AVal).grid(column=3, row=2, padx=4)
    self.boxC = Text(self.mainframe, state='normal', width=3, height=1, wrap='word', background=self.AVal).grid(column=4, row=2, padx=4)

    self.ABlob = ttk.Button(self.mainframe, text="A",style= 'mainSmall.TButton', command= lambda: self.getColour(self.boxA)).grid(column=2, row=3)
    self.BBlob = ttk.Button(self.mainframe, text="B",style= 'mainSmall.TButton', command= lambda: self.getColour(self.boxB)).grid(column=3, row=3)
    self.CBlob = ttk.Button(self.mainframe, text="C",style= 'mainSmall.TButton', command= lambda: self.getColour(self.boxC)).grid(column=4, row=3)

and:

def getColour(self,glyphRef):
    (triple, hexstr) = askcolor()
    if hexstr:
            glyphRef.config(bg=hexstr)

The problem is that I can't seem to reference self.ABlob in the way I am trying - it returns type None. I have tried including a pack.forget command in the button click func, but that also doesn't work.

Answer 1

The main part of your question seems to be:

The problem is that I can't seem to reference self.ABlob in the way I am trying - it returns type None

When you do x=ClassA(...).func(...), x contains the result of the call to func. Thus, when you do self.ABlob = ttk.Button(...).grid(...), what is stored in self.ABlob is None, because that is what is returned by the grid function.

If you want to store a reference to the button you will need to create the button and then call grid as two separate steps:

self.ABlob = ttk.Button(...)
self.ABlob.grid(...)

Personally I see this as a best practice, especially when you're using grid. By putting all of your grid statements in a block it becomes easier to visualize the layout and spot bugs:

self.ABlob.grid(row=3, column=2)
self.BBlob.grid(row=3, column=3)
self.CBlob.grid(row=3, column=4)